the wear and tear of the machinery and to the unevenness of
the running.

Taking the first of these difficulties into consideration it is
obvious that by means of a counterbalancing weight, about equal to
half that of the buoy, it is possible to cause the wave-power to
operate two ratchets, one doing work when the pull is to landwards and
the other when it is to seawards. Each, however, must be set to catch
the teeth of its own separate spur-wheel; and, inasmuch as the
direction of the motion in one case is different from what it is in
the other, it is necessary that, by means of an intervening toothed
wheel, the motion of one of these should be reversed before it is
communicated to the fly-wheel. The latter is thus driven always in the
same direction, both by the inward and by the outward stroke or pull
of the cable from the buoy.

Perhaps the most convenient development of the system is that in which
the spur-wheel is driven by two vertically pendant toothed bands,
resembling saws, and of sufficient length to provide for the greatest
possible amplitude of movement that could be imparted to them by the
motion of the buoy. The teeth are set to engage in those of the
spur-wheel, one band on each side, so that the effective stroke in one
case is downward, while in the other it is upward. These toothed bands
are drawn together at their lower ends by a spring, and they are also
kept under downward tension by weights or a powerful spring beneath.
The effect of this is that when both are drawn up and down the
spur-wheel goes round with a continuous motion, because at every
stroke the teeth of one band engage in the wheel and control it, while
those of the reversed one (at the other side) slip quite freely.

The shock occasioned by the blow of the ratchet on the spur-wheel, or
of one tooth upon another, may be reduced almost to vanishing point by
multiplying the number of ratchets or toothed bands, and placing the
effective ends, which engage in the teeth of the wheel successively,
one very slightly in advance of the other. In this way the machine is
so arranged that, no matter at what point the stroke imparted by the
movement of the buoy may be arrested, there is always one or other of
the ratchets or of the teeth which will fall into engagement with the
tooth of the spur-wheel, very close to its effective face, and thus
the momentum acquired by the one part before it impinges upon the
other becomes comparatively small.